1. Field of the Invention
The present invention relates to a broadcast receiver configured to receive broadcast signals transmitted for each channel and extract a broadcast signal of a channel desired by a user from the received broadcast signals.
2. Description of the Related Art
At the present day, broadcast receivers of a television broadcast are commercially manufactured in large numbers as types premised on moving a setting place thereof as well as types of setting. The latter type includes broadcast receivers such as a portable small broadcast receiver, cellular phone with a broadcast receiving function mounted thereon and an on-vehicle broadcast receiver. Recently, a large number of personal computers with broadcast receiving functions mounted thereon have been commercialized.
Most of the broadcast receivers are configured to assign channel numbers to an operation member for channel specifying (tuning) to view channels of the channel numbers assigned to the operation member operated by the user. However, channels of broadcast signals which can be received by the broadcast receiver are varied depending on the place where the broadcast receiver is. Some of the broadcast receivers, therefore, have functions to assign the channel numbers to the operation member (hereinafter, referred to channel assignment function). Such assignment is equivalent to the setting of the channels of the broadcast signals being objects to be taken out. As it stands now, a broadcast receiver based on the premise of the moving of the setting place frequently has to newly assign the channel numbers in accordance with the moving thereof.
The operation member to assign the channel numbers is mounted on a receiver main body or a remote control device. When the number of the operation members is smaller than that of the channels being objects to be assigned, a channel number with a relatively higher number is usually specified by operating one or more operation members multiple times. A plurality of operation members to change the channel numbers are prepared sometimes at every operation.
A conventional broadcast receiver with the aforementioned channel assignment function mounted thereon is disclosed by, for example, Japanese Patent Application Publication (KOKAI) No. 2003-158686. This patent document discloses a method for specifying channels capable of each receiving broadcast signal to assign them to an operation member while sequentially changing channels to be tuned. The patent document also discloses a method for checking the combination of the channels specified in this way with a combination of the receivable channels prepared by area and for assigning the specified channel to the operation member if the area is one which is matched to the combination of the specified channels.
Any method disclosed by the above-mentioned patent document performs an all station search to confirm whether or not broadcast signals can be received in all channels. However, the time required to search one channel is not a negligible length. The required time, specifically, is one or two seconds per one channel ordinarily. Nowadays, the number of the channels capable of transmitting the broadcast signals is usually in large. A terrestrial digital broadcast, for example, assumes fifty channels for the number of channels. In the days ahead, it is expected that the sales figures of the broadcast receivers based on the premise of the moving of the setting place, so that it is important for the broadcast receiver to further quickly assign the channels, namely, quickly set the channels being objects to extract the broadcast signals.